extractText/extractOcr/pdfToMarkdown's common return shape.
per-document and per-page QA metrics — see Report (src/types.ts)
Report
src/types.ts
every notice also delivered incrementally via onWarning, collected here in full (hybrid pages, auto-OCR-fallback, empty OCR pages, sparse-retry)
onWarning
extractText/extractOcr/pdfToMarkdown's common return shape.